surging

If its a lack of fuel due to a problem, it will usually die (fade-not skipping) then come back to life when you let off on the throttle. Cool Engine! They are pretty rare! By the way, if its the fuel pump and you go to replace it, beware that you cant buy the exact one with the filter in it (at least I couldnt find a new one). It should be a carter fuel pump. The replacement substitute I got bolts up fine but the pressure was a bit higher causing the carb to overflow when hot. Instead of trying to find a shorter rod, I built a 1/8" shim for it bringing the pressure to spec. a quick flow check of yours can be done by Unhooking the steel line to the carb and put a hose over it to a can. Run/turn it over and see what you get for fuel. If its that bad, you will hardly get any. Also remember theres a filter in the carb as well as the pump. Dont forget to check the flow into the pump. However, being as old as it is, its not a bad idea to change. Ours was still good but the diaphram was badly cracked. Good luck!!